1. Field of the Invention
This invention relates to electronic circuits, and more particularly, circuits that function as sources of voltage and current.
2. Description of the Related Art
As integrated circuit technology advances, the size of individual features within integrated circuits decreases. These smaller feature sizes can lead to competing demands in the design of these devices. In some cases, these competing demands pit maximum stress voltages for various transistor devices against voltage requirements.
Transistor devices in integrated circuit are typically rated for maximum gate oxide stress voltages, which are voltages between the gate terminal and one of the other transistor terminals. If the gate oxide voltage is exceeded for a given transistor, it may cause irreversible damage. Thus, the gate oxide voltages across transistors in a circuit is typically limited, by design.
However, in some cases, the rail-to-rail voltages required for a given circuit may compete with a requirement smaller gate oxide voltages. In some cases, these competing demands may result in a compromise on one or the other. For example, if the requirement for greater rail-to-rail voltages is critical, while the requirement for smaller devices (in terms of maximum gate oxide voltage), then larger devices may be used. Alternatively, if the requirement for smaller devices is more critical than the requirement for higher rail-to-rail voltages, the circuits may be designed using smaller rail-to-rail voltages. Yet a third way of meeting these competing demands may include the implementation of multiple voltage domains and the use of level shifter circuits.